EVIDENCE FOR DYNAMIC CLIMATE CHANGE ON TIMESCALES OF <1-5.5 M.Y. FROM THE CARBONIFEROUS ICE-PROXIMAL RECORD, NEW SOUTH WALES, AUSTRALIA

Late Paleozoic glacially-influenced deposits have been recognized from Gondwanan localities since the dawn of the 20th century, but a modern, critical sedimentologic evaluation and interpretation of these deposits from eastern Australia has been lacking. Detailed sedimentologic analysis of five glacially influenced Carboniferous formations from the Tamworth Belt of New South Wales, Australia is presented: the Spion Kop (earliest Namurian), Rocky Creek (latest Namurian to earliest Westphalian), and Johnsons Creek (mid-Namurian) Conglomerates, and the Currabubula (mid-Namurian to late Wesphalian) and Seaham (Namurian to late Stephanian) Formations. Facies analysis based on logged vertical sections and lateral facies relationships suggest sediment accumulated in a volcaniclastically influenced alluvial fan (facies association-FA1), fluvial (FA2), and lacustrine (FA3) landsystem with an eastward regional sediment dispersal pattern. Evidence for proglacial outwash fan (sandar), glaciofluvial, and glaciolacustrine deposition is preserved in the form of texturally diverse diamictite, outsized clasts in fine-grained facies, and rhythmically laminated sandstone and siltstone. Direct evidence of glaciation is not present throughout the stratigraphic extent of formations and facies trends are, thus, interpreted in terms of temporal patterns of glacial advance and retreat. Results suggest that the Tamworth Belt of New South Wales, Australia was subject to episodic, mountain/valley-type or outlet-type, temperate to subpolar glaciation during the Carboniferous. The timescale of glacial advance and retreat, and thus the internal pacing of climate in eastern Australia, is constrained to intervals of <1-5.5 m.y. using available biostratigraphic and radiometric age constraints and may include nested Milankovitch band cyclicity. Detailed sedimentary records of late Paleozoic glaciation from elsewhere on Gondwana, such as South America, Southern Africa, India, Oman, and Saudi Arabia also demonstrate highly fluctuating climatic conditions. These conclusions further support the view that the late Paleozoic glaciation was characterized by rapid and dynamic climatic shifts on multiple timescales, which is comparable to the character of Cenozoic climate.